(19)

(11)

EP 0 897 599 A1

(12)

(43) Date of publication: 24.02.1999 Bulletin 1999/08 (21) Application number: 97905313.0 (22) Date of filing: 03.03.1997

(51) International Patent Classification (IPC):  H01P 1/ 20( . ) H01P 1/ 203( . ) (86) International application number: PCT/GB1997/000573 (87) International publication number: WO 1997/033335 (12.09.1997 Gazette 1997/39)

(84) Designated Contracting States: DE FR GB IT NL SE (30) Priority: 06.03.1996 GB 19960004731 (71) Applicant: CENTRAL RESEARCH LABORATORIES LIMITED Hayes, Middlesex, UB3 1HH (GB)	(72) Inventors: SEYMOUR, Colin Hayes, Middlesex UB3 1HH (GB) COUCH, Nigel Hayes, Middlesex UB3 1HH (GB) (74) Representative: Leaman, Keith, et al  QED Patents Limited, Dawley Road Hayes, Middlesex UB3 1HH Hayes, Middlesex UB3 1HH (GB)